Nim (Abigail Breslin) lives a regular Nim's Family Robinson life on her own deserted isle in "Nim's Island," the reasonably delightful new kids' fantasy film based on Wendy Orr's novel.

She swings among the trees, spends her days with her pals — a sea lion, a pelican and a lizard — and her nights with her books and her dad, the marine biologist (Gerard Butler).

But when dad goes missing, Nim has to reach out by e-mail to the one "hero" she knows — Alex Rover, the title character in a series of adventure novels.

Ah, but "Alex Rover" isn't who he seems to be — who she seems to be. "Alex" is "Alexandra." And she (Jodie Foster) is not exactly an adventurer, escaping from Bedouin raiders in the desert, battling natives who want to toss her, him, into a volcano. Alex is a "borderline agoraphobic," an obsessive-compulsive shut-in lashed to her computer, researching and writing her "Alex Rover" novels, a woman who goes through Purell hand-sanitizer by the case, who subsists on Progresso soup and is too frightened of the outdoors to even get her own mail.

She'll make a great rescuer, won't she?

This colorful, winning comedy allows the plucky little girl to fend off rapacious tourists who invade her island as she waits for her shipwrecked dad to return, or her literary hero to come to her rescue. And it gives Foster the chance to act the heck out of a fearful woman who faces those fears to answer a child's cry for help. What is she so afraid of?

"Everything!"

Alex has a mantra, one she wrote for her swarthy, swashbuckling alter ego (Gerard Butler, too), his ghostly presence hanging over her shoulder, nagging her on to take this one great adventure.

"I must be the hero of my own life story!" All those yummy ingredients come pretty close to a boil in "Nim's Island." But the Oscar-winning Foster's visible struggles with the material vividly illustrate the truth in what the old actor said, "Dying is easy, comedy is hard." The engaging Butler reminds us that, as yet, he can't be both larger than life and funny (Kurt Russell would have killed in this part). At least the kid-and-critters bit lives up to its billing. Your 10-and-unders will be tickled at this.

Walden Media, which produced this, is still more a great idea, full of potential, than it is the Tiffany's of children's filmmaking. Like earlier Walden productions "Because of Winn-Dixie," "The Bridge to Terabithia," "Hoot" and "The Chronicles of Narnia," "Nim's" is almost but not quite first-rate. The production values are Walden's best yet. But the adventure is a little shy of magical, the comedy just short of hilarious, the whimsy forced. Working with children's material, they aren't able to attract the best writers.

Still, hiring the greatest screen actress of her generation pays some wonderful dividends. Foster may be a bit at sea when it comes to the comedy (upstaged by a sea lion, a first for her), but she is a perfectly credible agoraphobic. And in a couple of emotional moments, she makes us believe that her shut-in, Alexandra, is genuinely worried for the e-mailer she has just learned is a little girl, lonely and in trouble, in the middle of nowhere. Foster also manages the physical-fear shtick well enough to make us forget that we're watching a cut-rate special effect of a woman rowing a tiny dory in a raging monsoon.

Butler's sense of playfulness is never fully realized. He's got the funny brogue, the dashing looks, the presence to be the next Indiana Jones. They don't give him license to play this alter ego as broadly as one would have hoped. His "Alex Rover" should have been a blow-hard, all bravado, swagger and derring-do. The "300" star plays this fictional "hero" with one arm (his funny arm) tied behind his back.

However, the once-and-future "Miss Sunshine," Breslin, is just terrific playing this positive role model. Her Nim is resourceful, independent and reliable. And when things go wrong, she knows to reach out for adult help.

All things considered, the movie does a good enough job of filling that void of kid films between cartoons and "The Sisterhood of the Traveling Pants." It's worth spending 90 minutes on "Nim's Island." You just wouldn't want to get stranded there.